1. Field of the Invention
The present invention relates to an optical transmission method and system for carrying data transmission with use of optical fiber. More particularly, it concerns an optical transmission method and system preferable in high-speed data transmission to a long distance.
2. Description of the Prior Art
Prior arts related to the optical transmission system include, for example, the technique disclosed in the Japanese Patent Application Laid-Open 3-296334.
However, it is demanded to accomplish an optical transmission system operating at further higher speed since development of the modern information society has increased long-distance communication traffic in recent years. Also, it is desired that the optical transmission system can transmit data to further longer distance without repeat in view of reliability and cost of the system.
Furthermore, the number of fields to which an optical transmission system is applied has been increased with the recent development of the information society. For the reason, it is needed to accomplish the optical transmission system having a variety of functions and capacities to satisfy specific requirements.